Periodontal diseases are thought to be infectious diseases caused by bacteria present in dental plaques. Tooth brushing is a highly effective method to remove dental plaque from the teeth. Power toothbrushes can enhance the removal of dental plaque. Such power toothbrushes have a set of bristles attached to a brush head which is moved by a driver that causes the bristles to scrub dental surfaces.
The brush heads of both manual and power toothbrushes comprise bristles which are used to clean the teeth, tongue, and cheeks. In some toothbrushes, the bristles are organized into bristle tufts contained within retention rings. The retention rings serve to secure the bristle tufts within the brush head and often have a hollow circular shape with an interior and exterior circular circumference. During manufacture, the bristle tufts are inserted into the hollow interior of the retention ring, and the bristles are then fused together using heat to form a head which cannot be pulled out through the retention ring.
Often, however, the retention rings are not firmly secured within the brush head. As a result, the ring and bristle tuft can be or become loose within the brush head, and the bristles might not always be positioned at an angle optimal for brushing. As such, under the dynamic conditions of motion induced by the power toothbrush operation, for example, the bristle tuft structure can undergo higher stresses under the dynamic motion, which could lead to separation. Further, the process of organizing the bristles into tufts within the retention rings and then cooling the brush head material, or allowing it to cool, in order to fix the tufts in place can be time-consuming and expensive.
Accordingly, there is a need in the art for brush head assemblies, and methods of their manufacture, that permanently and efficiently retain bristle tufts within the brush head.